It is nice that it validates but I would change a few things...
Firstly you use inline-styling (eg, the wrapping div) which (for me at least) is a no-no!
Secondly, there is div-div-div galore. Try using more appropriate tags where... appropriate; a H1 tag for the main heading (or branding, or whatever), various sub-heading tags, spans, etc.
Thirdly, there are lots of extra tags which strictly are unnecessary. Eg, in the "left_content_section" under "<!-- UPDATES -->" you have "<div class="text"><br /></div>" which is really really not needed!
Fourthly, you have class="text" for most things - why not just get rid of that and set element-based styles rather than class-based?

Don't get me wrong, striving to be standards compliant is great and you have dont a great start by getting it validated XHTML Strict but the road to 'clean' XHTML/CSS doesn't stop there.

If you need any pointers I will be more than willing to help out!

- Salathe

P.S. I like the design itself if that is any consolation.